Hardware dongles like the Brook Wingman XE work, but they cost $40+. PS3XPAD is free and often has lower input lag because it runs directly inside the PS3’s I/O processor.
The plugin can be enabled/disabled on the fly via a simple file presence on the internal HDD or USB drive. ps3xpad
An FTP client (like WinSCP or FileZilla ) or a FAT32-formatted USB drive. Hardware dongles like the Brook Wingman XE work,